(JTA) — An Orthodox Jewish professional mixed martial arts fighter was fatally shot in his South Florida home.

Aaron Rajman, 25, was killed Monday evening when several men entered his home in West Boca Raton. The men reportedly argued with Rajman and shot him before driving away, the Sun-Sentinel newspaper reported, citing the Palm Beach County Sheriff’s Office. It is not known what they argued about.

Rajman turned professional in 2014 and held a 2-2 record after winning several MMA titles as an amateur. He is believed to be the only Orthodox Jewish MMA fighter, according to reports.

“This was a special young man who had a heart of gold. It’s a tragedy,” Rabbi Zalman Bukiet, director of the Chabad of West Boca Raton, told the local news station WPTV-Ch. 5.

Rajman reportedly studied Torah at the Chabad and taught children at a local Jewish school, as well as self-defense classes for children and Krav Maga techniques to local police. Krav Maga is a self-defense system developed for the Israeli army.